$-\dfrac{4}{6} - \dfrac{2}{5} = {?}$
Answer: $ = - {\dfrac{4 \times 5}{6 \times 5}} - {\dfrac{2 \times 6}{5 \times 6}} $ $ = - {\dfrac{20}{30}} - {\dfrac{12}{30}} $ $ = - \dfrac{{20} - {12}}{30} $ $ = -\dfrac{32}{30}$